Promotional calls

Received a call at 26:49 on 11 April from Afrizone by this number *** on behalf of MTN offering a promotional product. Firstly, I would like to know who/which company I consented with to be contacted by you and where is the signed consent for my details to be used for promotional products ? Secondly, these calls happen after business working hours according to your company profile on website and a lot of times these agents just call to breath 5 seconds into the call without saying a word and then hang up.Thirdly, I’m a Vodacom customer and so I don’t understand why the agreement about sharing my details was with MTN and Afrizone. Popi Act??